The childish and a bit immature girl serving as the A-Chair (Ace Chair), she is one year junior to Amu. Yaya likes the sweets baked by Nadeshiko. Her hair is tied in pigtails with two big ribbons. She does not know how to swim. She is also a ballerina, though a rather clumsy one.

She has newborn baby brother named Tsubasa, who, she claims, gets all her parent's attention. It is because of this that her Guardian Character, Pepe, is a baby, because she claims that babies get all of the attention.

Her Character Change character is a baby that uses a giant rattle as weapon; influenced by the "baby" character, she has a crybaby personality. Pepe says "Pretty, Cutie, Love Baby!" during a Character Change with Yaya.

Yaya reaches the Character Transformation with Pepe in episode 41 of the anime. Her Transformation is called Dear Baby.